Synergistic inhibition of platelet aggregation by endothelium derived relaxing factor and prostacyclin

Abstract

The anti-aggregatory effect of endothelium-derived relaxing factor (EDRF) on aggregation of washed, aspirin-treated platelets was compared with that of nitric oxide. Nitric oxide produced a dosedependent inhibitory effect on PAF-induced aggregation: the antiaggregatory activity was unstable and was completely preventable by pretreating the platelets with haemoglobin (10 μmol/1). Bovine aortic endothelial cells (EC) were grown to confluence on microcarrier beads, pretreated with aspirin (1 mmol/1), and their addition to the platelet cuvette also caused a dose dependent inhibition of aggregation induced by PAF, thrombin and A23187. The inhibitory effect of the EC on platelet aggregation was pa..